Speed reducer base



FIG. 1 is a perspective view of speed reducer base showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The portions shown in dashed lines do not form part of the design. 

The ornamental design for speed reducer base, as shown and described. 